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poj 3067 Japan(树状数组)

Japan
Time Limit: 1000MS   Memory Limit: 65536K
Total Submissions: 23111   Accepted: 6232

Description

Japan plans to welcome the ACM ICPC World Finals and a lot of roads must be built for the venue. Japan is tall island with N cities on the East coast and M cities on the West coast (M <= 1000, N <= 1000). K superhighways will be build. Cities on each coast are numbered 1, 2, ... from North to South. Each superhighway is straight line and connects city on the East coast with city of the West coast. The funding for the construction is guaranteed by ACM. A major portion of the sum is determined by the number of crossings between superhighways. At most two superhighways cross at one location. Write a program that calculates the number of the crossings between superhighways.

Input

The input file starts with T – the number of test cases. Each test case starts with three numbers – N, M, K. Each of the next K lines contains two numbers – the numbers of cities connected by the superhighway. The first one is the number of the city on the East coast and second one is the number of the city of the West coast.

Output

For each test case write one line on the standard output: 
Test case (case number): (number of crossings)

Sample Input

Sample Output

Source

 
树状数组第三题。
这道题可以先排序,x升序,x相同的时候,y升序
然后求y中的逆序对数。
大概知道了怎么用树状数组求逆序对。
下标(从0开始)-比a[i]小的=a[i]与之前形成的逆序对数。
具体见代码注释
 

 

 

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